The invention is directed to a previously unknown combination of one or more cationic starch(es) and aluminum salts to produce a composition which can detackify paint at lower doses than those required using conventional treatments while providing improved handling and a more “green” environmental profile.
Methods and compositions for detackifying and dispersing, and coagulating/flocculating and dispersing solvent borne and waterborne paints, respectively, in paint spray booth waters are disclosed. An aqueous composition of water soluble cationic starch polymer, is used in conjunction with an aluminum compound to treat the paint spray booth waters.
In the automotive and related coatings industries, it is estimated that between 20 to 40% of the total volume of paint sprayed is overspray. In the application of organic paints such as epoxy resins, high solids enamel paints and the like, it is necessary to trap the oversprayed paint. In large industrial applications such as auto body coating, this is accomplished by the use of water curtains on the interior booth walls, whereby the oversprayed coating material is incorporated into the water as it cascades down the walls of the booth into a reservoir.
Typically, this water is recirculated back to the booth by means of recirculating pumps. The agglomeration and accumulation of live coating material in the water of the paint spray booth results in serious problems such as blockage of the pipes and circulating pumps as well as an accumulation of paint on the walls of the paint spray booth behind the water curtain. As more and more coating material is sprayed in the booth, the overspray material removed from the air builds up in the water in the form of tar-like coherent sludge which in a short time can foul the pumps and lines which circulate the booth's water. Furthermore, this sludge is extremely difficult to remove from the pump, lines, reservoir, and other internal surfaces of the system with which it comes in contact. The accumulation of raw paint masses in the water reservoir also creates serious maintenance problems when the system is periodically cleaned out, requiring much effort to remove the heavy build-up of coating material from the reservoir.
It is desirable, to treat the water in the paint booth in such a way as to render the over-sprayed coating material free of stickiness and tackiness so that it readily separates from the water, does not adhere to the spray booth walls, pipes, pumps; or other surfaces and internal components of the spray booth system, and maintains a floating, detackified condition.